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Technical Discussion » Read volume or point cloud in shader
- kelvincai
- 74 posts
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In shader/render, it is in camera space, you need to transform the sampling position to world space when sampling the vdb at shader.
Technical Discussion » Iterate over Point Cloud in Material Shader
- kelvincai
- 74 posts
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Interesting idea. However, in order to get the ripple vop to project on the flip mesh, the flip mesh needs to have consistent uv. The topology is changing in the flip mesh so it hard to get consistent uv on it.
The first step I would try is to use the dual rest generated in the flip sim to get a consistent uv on the mesh.
The first step I would try is to use the dual rest generated in the flip sim to get a consistent uv on the mesh.
Technical Discussion » Aiming RBD objects
- kelvincai
- 74 posts
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Calculate the vector from the centroid of the RBD object to the target point. Then calculate the force(a portion of the vector length) and direction(the normalized vector) needed from the vector.
Technical Discussion » Remap Pyro Opacity based on age?
- kelvincai
- 74 posts
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Technical Discussion » Ocean simulation question (s)
Technical Discussion » Distributed Simulation looks wrong !
- kelvincai
- 74 posts
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Unlike flip, the pressure solve in pyro is not distributed (ie. the containers were not treated as one by all the machines). In pyro, the containers are treated independently by each machine with overlap.
Until SESI implemented distributed pressure solve for the multigrid node used in pyro, distributed pyro will look different than a single container pyro.
You could also try replacing the multigrid pressure solve node in pyro with the variational pressure solve node used in flip to see if you could distribute the pressure solve. The variational pressure solve node used in flip is the only node can do distributed pressure solve in Houdini right now.
Until SESI implemented distributed pressure solve for the multigrid node used in pyro, distributed pyro will look different than a single container pyro.
You could also try replacing the multigrid pressure solve node in pyro with the variational pressure solve node used in flip to see if you could distribute the pressure solve. The variational pressure solve node used in flip is the only node can do distributed pressure solve in Houdini right now.
Technical Discussion » Guided Ocean Layer SIM missing frames
- kelvincai
- 74 posts
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If Save In Background is turned on, it would take sometime to save the frame, especially for large file.
Technical Discussion » EXR Metadata in COP
- kelvincai
- 74 posts
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Is there a way to create/export exr metadata in COP?
Tried the Metadata COP. But it seems it doesn’t export the metadata to the resulting exr files.
Tried the Metadata COP. But it seems it doesn’t export the metadata to the resulting exr files.
Technical Discussion » should I continue a sim if it runs out of ram?
- kelvincai
- 74 posts
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If it is still running and both vram and ram ran out, it is probably hitting the swap, hence the slowness.
Technical Discussion » i love vops but hate vex
- kelvincai
- 74 posts
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Work in Progress » Finished Work: VIRTUS
- kelvincai
- 74 posts
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http//vimeo.com/95514470
FX were sim in Houdini and Maya (FumeFX). Fire rendered in Mantra and deep comp in Nuke with hard surface rendered in Arnold.
FX were sim in Houdini and Maya (FumeFX). Fire rendered in Mantra and deep comp in Nuke with hard surface rendered in Arnold.
Edited by - May 19, 2014 17:06:56
Technical Discussion » deep layer names not consistent with channel names in Nuke
- kelvincai
- 74 posts
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Hello, everyone,
I rendered a color layer and deep layer to my teammate. He got the following problem in Nuke 8.0v2 and 8.0v4.
Does anyone also have similar problem? I am not sure whether I did any incorrect setting.
Thanks,
As I am suppose using a color layer with multiple channels eg.diffuse, specular etc., and than using ‘DeepRecolor’ node to recolor the deep data layer which has the same channels. Before importing those two layers in Nuke, I've found that their own channel names are as follows
Color Layer
Deep Layer
However when both layers imported together, their channel names change its order
Channel disorder
This makes their channels mismatch and give a wrong color display. Finally I use a ‘Expression’ node to correct their channels
Expression node
But I'm not sure this is the best way to fix this or even it is one of the bugs in Nuke. And I would be very grateful if anyone can help~
I rendered a color layer and deep layer to my teammate. He got the following problem in Nuke 8.0v2 and 8.0v4.
Does anyone also have similar problem? I am not sure whether I did any incorrect setting.
Thanks,
As I am suppose using a color layer with multiple channels eg.diffuse, specular etc., and than using ‘DeepRecolor’ node to recolor the deep data layer which has the same channels. Before importing those two layers in Nuke, I've found that their own channel names are as follows
Color Layer
Deep Layer
However when both layers imported together, their channel names change its order
Channel disorder
This makes their channels mismatch and give a wrong color display. Finally I use a ‘Expression’ node to correct their channels
Expression node
But I'm not sure this is the best way to fix this or even it is one of the bugs in Nuke. And I would be very grateful if anyone can help~
Technical Discussion » h13 deep exr 2.0 to nuke8
- kelvincai
- 74 posts
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I don't think nuke 7 support exr 2.0 deep data. And h13 mantra render exr 2.0 deep data in dcm
Technical Discussion » h13 deep exr 2.0 to nuke8
- kelvincai
- 74 posts
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rendered a dcm .exr from h13. However, the .exr is black in nuke8v1. In mplay, the .exr is not black.
In nuke8, the DeepSample node could display sample data.
Using iinfo dcm.exr, the WorldToCamera and WorldToNDC matrices are all zero. Is it a bug?
File ./dcm.exr (OpenEXR format)
Resolution 1920 x 1080
Pz
Data 32 bit float
Color Model Single Channel
Channel Depth 32 x 1 (32 bpp)
Of (r,g,b)
Data 16 bit float
Color Model RGB
Channel Depth 16 x 3 (48 bpp)
C (r,g,b)
Data 16 bit float
Color Model RGB
Channel Depth 16 x 3 (48 bpp)
A
Data 16 bit float
Color Model Single Channel
Channel Depth 16 x 1 (16 bpp)
Depth-Complexity
Data 16 bit integer
Color Model Single Channel
Channel Depth 16 x 1 (16 bpp)
Format Specific Information
Image Type Deep
Compression zips
Comment none
Created 20140129 173713
Depth Interpolation discrete
Samples Composited true
WorldToCamera [ 0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0]
WorldToNDC [ 0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0]
In nuke8, the DeepSample node could display sample data.
Using iinfo dcm.exr, the WorldToCamera and WorldToNDC matrices are all zero. Is it a bug?
File ./dcm.exr (OpenEXR format)
Resolution 1920 x 1080
Pz
Data 32 bit float
Color Model Single Channel
Channel Depth 32 x 1 (32 bpp)
Of (r,g,b)
Data 16 bit float
Color Model RGB
Channel Depth 16 x 3 (48 bpp)
C (r,g,b)
Data 16 bit float
Color Model RGB
Channel Depth 16 x 3 (48 bpp)
A
Data 16 bit float
Color Model Single Channel
Channel Depth 16 x 1 (16 bpp)
Depth-Complexity
Data 16 bit integer
Color Model Single Channel
Channel Depth 16 x 1 (16 bpp)
Format Specific Information
Image Type Deep
Compression zips
Comment none
Created 20140129 173713
Depth Interpolation discrete
Samples Composited true
WorldToCamera [ 0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0]
WorldToNDC [ 0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0]
Technical Discussion » illuminance loop strange behaviour
- kelvincai
- 74 posts
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Technical Discussion » URGENT help needed - Partical Colors and Transperency
- kelvincai
- 74 posts
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Technical Discussion » URGENT help needed - Partical Colors and Transperency
- kelvincai
- 74 posts
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rand($ID) at the param
You have to render the particle as point, or other primitive at the Render POP, and assign a shader which takes its alpha attribute.
You have to render the particle as point, or other primitive at the Render POP, and assign a shader which takes its alpha attribute.
Technical Discussion » set param through python
- kelvincai
- 74 posts
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maybe
expression = “strmatch(chs(”../object_merge1/objpath1“), ”“)”
path = “.” //path of the node you intended to set the parm
hou.node(path).parm(“input”).setExpression(expression)
expression = “strmatch(chs(”../object_merge1/objpath1“), ”“)”
path = “.” //path of the node you intended to set the parm
hou.node(path).parm(“input”).setExpression(expression)
Technical Discussion » Help needed rendering a textured 3d model to a 2d image
- kelvincai
- 74 posts
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The model should be UV unwrapped already if you bought it from a known vendor. After importing the FBX files, there should a material SOP inside the SubNet. You could modify the shader/material in there.
However, Houdini is not the same as other 3D package. You have to get used to its workflow. Once you get a hold of it, it is very powerful.
Try the intro tutorials of Digital Tutor or 3D Buzz to get you up to speed.
However, Houdini is not the same as other 3D package. You have to get used to its workflow. Once you get a hold of it, it is very powerful.
Try the intro tutorials of Digital Tutor or 3D Buzz to get you up to speed.
Technical Discussion » How does the refraction mask work?
- kelvincai
- 74 posts
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it might be the total internal reflection which reflect the env. I am not sure though.
How about try a thin sheet and see if it refract the objects behind it?
How about try a thin sheet and see if it refract the objects behind it?
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